1. Field of the Invention
The present invention pertains to a shock absorber. More particularly, the present invention pertains to a shock absorber having a twin tube construction. Even more particularly, the present invention pertains to a twin tube construction shock absorber having unidirectional fluid flow.
2. Description of the Prior Art
Shock absorbers are well known in the art, such as found in U.S. Pat. No. 2,804,513 to Oppel; U.S. Pat. No. 5,588,510 to Wilke; U.S. Pat. No. 6,648,109 to Farr et al.; U.S. Pat. No. 6,913,126 to Dohrmann et al.; as well as U.S. Patent Publication No. 2002/0121416 to Katayama et al. The shock absorbers disclosed by Oppel, Wilke, Farr, Dohrmann, and Katayama are representative of the types of shock absorbers that are commonly available. Such shock absorbers generally comprise a cylinder and a piston, the piston being connected to a rod which experiences a load. Fluid is contained within the cylinder. As the piston experiences compression and rebound strokes, fluid is forced out of one side of the cylinder and fluid is forced into the other side through a series of valves. The valves may be disposed on the external portion of the shock absorber. The shock absorber may also provide additional external components for controlling the flow of fluid from one side of the cylinder to the other, thereby controlling the damping force of the shock absorber.
However, such existing designs require a series of complex valve components which can be expensive, difficult to maintain, and difficult to assemble. In addition, shock absorbers using this construction rely upon a series of valves to control the variability of the damping. Therefore, it is difficult to variably adjust the damping rate for these shock absorbers.
Thus, there remains a need for a shock absorber which has a simpler construction, requires less moving parts, allows for easy adjustment of the damping force, and which preferably requires the same or less room than shock absorbers which are found in the prior art.
The present invention, as is detailed hereinbelow, seeks to resolve these issues by providing a twin-tube construction shock absorber which has unidirectional fluid flow throughout the system and which comprises a minimal number of moving parts, and which may additionally have the damping force adjusted easily and/or remotely.